In the irrigation industry today, many different types of water sprinklers are provided. In many cases, the nozzle is carried on a sprinkler having some mechanism for rotating the nozzle around in a circle. Some such rotary sprinklers also comprise "pop-up" sprinklers. In a "pop-up" sprinkler, the nozzle is carried on the upper end of a "riser" which is normally retracted into an outer sprinkler body buried in the ground.
One well known type of rotary, pop-up sprinkler is the Series 300, Stream Rotor sprinkler manufactured and sold by The Toro Company. The nozzle used in a Stream Rotor sprinkler is made of a lower nozzle piece fixed, as by sonic welding, to an upper nozzle piece. The nozzle includes a series of radially extending nozzle channels which end in a series of outlet ports spaced around the nozzle. Thus, the nozzle throws out a series of radial water streams which rotate around in a circle as the nozzle is rotated by the drive train, giving rise to the name "Stream Rotor".
The pattern of rotating water streams provided by a Stream Rotor nozzle is aesthetically pleasing to many people. In addition, the radius of throw for a given water pressure is increased by forming the water into distinct streams. However, prior to the present invention, it was not possible to easily and quickly adjust the throw radius of a Stream Rotor nozzle. This fact complicated the design and installation of irrigation systems.
For example, if an area is irrigated by multiple Stream Rotor sprinklers, each sprinkler will water a circular area determined by the maximum throw radius of the nozzle. The area of coverage of adjacent sprinklers should desirably overlap a small amount to properly water the area. However, overwatering will result if the sprinkler coverage overlaps too much. Thus, it is often necessary to decrease the throw radius of certain sprinklers to achieve the proper coverage and best results.
Prior to the present invention, for a given water pressure it was the practice to adjust the throw radius by changing nozzles on the sprinkler. Different nozzles were provided by the manufacturer with each nozzle being individually designed to throw water to a certain maximum radius while flowing a certain number of gallons per minute. An installer who needed to decrease the radius of throw of a certain sprinkler would simply choose a nozzle designed to throw to the necessary radius and install that nozzle on the sprinkler. This adjustment process might be required for quite a few sprinklers in an entire irrigation job.
Unfortunately, the need to have on hand an entire array of different nozzles to adjust throw radius complicates the installer's business. If an installer is out of stock on a particular nozzle, and that nozzle is required in a job, then the installer has to go and get one to complete the job, costing him or the customer time and money. Alternatively, the installer might be tempted to simply install the wrong nozzle on the sprinkler to save the aggravation of having to get the right nozzle. However, this would leave an irrigation system which is not operating as well as it should.